Transwestern staff also regularly inspects and maintains the heating and air conditioning equipment used in the building to optimize its performance and prolong its life, Howard said. The Housing Center's continued Energy Star designations save money and energy while they also send a strong signal regarding housing industry support for voluntary energy guidelines, he added.

NAHB has also made landscaping improvements around the building, adding more plants and greenery to help absorb storm water runoff and keep it out of the city's drainage system - not an Energy Star requirement, but another way to reduce the environmental impact of the National Housing Center.

"Many of our members build homes with appliances, windows and doors, and heating and cooling systems that meet the Energy Star guidelines. In fact, 840,000 Energy Star -rated homes have been constructed in the past 15 years," Howard noted. "These home builders' business practices show how NAHB members are at the forefront of green building - and that's reflected in how we operate our national headquarters."

A plaque recognizing the Energy Star achievement has been posted near the building's entrance.